The applications of polyurethanes (PEUs) in medicine continue to increase due to their excellent mechanical properties, blood compatibility, and biostability. However, serious shortcomings in blood compatibility and biostability have been identified for conventional segmented block copolythanes. We have recently found a high platelet reactivity for conventional PEUs and found that many surface chemical functionalities of conventional PEUs are susceptible to degradation by agents similar to those in the inflammatory sequence. We have synthesized PEUs with surfaces dominated by hydrocarbon moieties that show extremely low platelet reactivity, and may be resistant to biodegradation and calcification. This project is directed towards the development of PEUs with improved blood compatibility, and enhanced resistance to biodegradation and calcification. New PEUs with high surface concentrations of hydrocarbon and fluorocarbon groups will be made and characterized with ESCA and SIMS. The susceptibility of the PEUs to oxidation and enzymatic attack will be assessed in vitro. Protein adsorption studies will evaluate the ability of the PEUs to adsorb selectively albumin from plasma, and measure the surface albumin retention strength. Endothelial cell growth on these polymers will be evaluated. Finally, the susceptibility of the PEUs to calcification will be assessed in vitro .